A student makes four resistors using different pieces of wire. The wires have different diameters and lengths, but are all made of the exact same material.
| Wire | Diameter / mm | Length / cm |
|---|---|---|
| A | 0.5 | 12 |
| B | 0.5 | 25 |
| C | 1.5 | 12 |
| D | 1.5 | 25 |
Which piece of wire will make the resistor with the smallest resistance?
Wire A
Wire B
Wire C
Wire D
452 exam-style questions on CIE IGCSE Physics 4.2 Electrical quantities, covering 4.2.1a Positive and negative charge, 4.2.1b Charging by friction and detecting charge, 4.2.1c Electrical conductors and insulators, 4.2.1d Electric fields and electric field patterns, 4.2.2a Electric current, charge and measuring current, 4.2.2b Conduction in metals and the direction of current, 4.2.2c Direct current and alternating current, 4.2.3a Electromotive force, 4.2.3b Potential difference and voltmeters, 4.2.4a Resistance, 4.2.4b Resistance of a metallic wire, 4.2.4c Current–voltage graphs, and 4.2.5 Electrical energy and electrical power. Each one has a worked solution and a mark scheme showing where the marks go.